Embedded Linux Character Device Driver (Read/Write)

This repository is a Character Device Driver project I developed to understand and implement the working logic of Embedded Linux systems at the kernel level.

Developed on Raspberry Pi, this project demonstrates the capabilities of dynamically adding/removing modules to the Linux kernel, creating virtual files, and exchanging data between user space and kernel space.

🎯 Project Objectives and Technical Gains

As an engineer, I aimed for and implemented the following in this project:

• Kernel Space vs User Space: Going beyond standard C code to run code in Kernel Space, the restricted and privileged area of the operating system.
• LKM (Loadable Kernel Modules): Mechanisms for loading (insmod) and unloading (rmmod) drivers at runtime without recompiling the kernel.
• Device Driver Architecture: Creating virtual devices under /dev, in line with Linux's “Everything is a file” philosophy.
• Secure Data Transfer: Using the copy_from_user and copy_to_user functions, which provide secure memory access instead of raw pointer access, when receiving data from the user to the kernel.
• File Operations (fops): Implementation of how standard open, close, read, write system calls are handled on the driver side (callback functions).

🛠 Technologies and Tools Used

• Hardware: Raspberry Pi 4 (ARM Architecture)
• Operating System: Raspberry Pi OS (Linux Kernel 6.x/5.x)
• Language: C (GNU C Standard)
• Compilation: Makefile & GCC (Cross-Compilation logic)
• Kernel Tools: dmesg, insmod, rmmod, lsmod

🚀 Installation and Testing (How to Run)

To test this driver in your own Raspberry Pi environment, follow these steps:

1. Compile

Use Makefile to create the Kernel object (.ko):

make